Dispensing system for fluid substances

ABSTRACT

The invention relates to a delivery system for fluid substances, which comprises a plunger-type syringe in the form of a cartridge having at least one injectate chamber, which injectate chamber is provided with an injection plunger, and an attachment mounted on the cartridge at its delivery-side end, characterised in that the attachment is mounted on the cartridge by means of a releasable snap closure.

The present invention relates to a delivery system for fluid substances.It relates especially to a delivery system comprising a plunger-typesyringe in the form of a cartridge having at least one injectate chamberprovided with an injection plunger, and an attachment mounted on thecartridge at its delivery-side end.

Such delivery systems are already known in the prior art. For example, adouble-barrel plunger-type syringe is used, which comprises a cartridgecomposed of two axially parallel, adjacently arranged injectate chamberswith injection plungers guided therein, on which a mixer tip is mounted.The mixer tip has hitherto been mounted by simply being pushed on or bymeans of a screw connection (Luer lock closure) for which theplunger-type syringe is provided with an internal or external thread inwhich the mixer tip, which is provided with a complementary thread,engages.

The solutions known in the prior art for mounting attachments on theplunger-type syringe are, however, associated with considerabledisadvantages. For example, when highly viscous fluids are being used,push-on connections do not provide a secure connection because theygenerally do not withstand the higher plunger pressure that is necessaryin such a case. Although that problem does not arise in the case of Luerlock closures, there is a risk, especially in the case of highly viscousfluids, that contamination will occur when the attachment is mounted andremoved as a result of smearing of outlet openings of the cartridge.

The aim of the present invention is to overcome the disadvantages of thesolutions for mounting an attachment on a plunger-type syringe known inthe prior art. That aim is achieved according to the invention by thefeatures of the independent claim. Advantageous configurations of theinvention are given in the subsidiary claims.

According to the invention there is provided a delivery system for fluidsubstances which comprises a plunger-type syringe and an attachmentmounted thereon. The plunger-type syringe comprises a cartridge havingat least one injectate chamber which is provided with an injectionplunger. When the cartridge has a plurality of injectate chambers,injection plungers can be pushed into or withdrawn from the injectatechambers either separately or together, the injection plungers in thelatter case advantageously being joined to one another by a suitableconnecting element.

A characteristic feature of the invention provides that the attachmentis mounted on the cartridge by means of a releasable snap closure. Thereleasable snap closure can, in principle, have any desiredconfiguration, provided it is ensured that when the snap closure islocked into place a protuberance of any desired nature locks into agroove of any desired nature by resilient-plastic deformation of thecartridge and/or the attachment. For example, the snap closure can takethe form of a sliding sleeve mounted on the attachment and having aninternal annular collar which is pushed over an outer annular collarmounted on the outer side of the cartridge. The locking into place ofthe snap closure is preferably accompanied by an audible clicking sound,so that the locking-in can be monitored acoustically by the user.

In an embodiment of the invention that is preferred according to theinvention there are formed on the attachment, for the purpose of itsbeing mounted on the cartridge by means of a snap closure, two hookswhich lie substantially diametrically opposite one another. The hookseach engage in undercut grooves which are arranged facing the hooks,each groove being arranged on a resilient arm which is resilientlybiased on being deflected out of its rest position. In order that thehooks are able to enter into engagement with the undercut grooves it isfirst necessary to overcome the resilient spring force of the resilientarms. When the hooks are in engagement with the undercut grooves, theresilient spring force of the resilient arms in the same way ensuresthat the hooks are secured against release.

The resilient arms can especially be in the form of portions of anelement (locking clip) mounted on the delivery-side end of thecartridge, it being possible for the cartridge and the locking clip tobe manufactured separately and then joined together. Conventionalcartridges can thus advantageously be provided with the locking clipcarrying the resilient arms for the snap closure, so that even alreadymanufactured cartridges can subsequently be provided with a snapclosure.

In an advantageous, very simple embodiment of the locking clip, thelatter takes the form of (incomplete) rings which engage around theoutlet openings of the cartridge, the rings being joined to one anotherby at least one rib-like element. In such a case the resilient armshaving the undercut grooves project symmetrically from the rings so thaton rotation of the cartridge through 180° about its longitudinal axisthey can take each other's places.

Furthermore, for the resilient deflection of the resilient arms theresilient arms can be provided with pressure faces in the form of planarwidened portions. When a sufficient pressing force is exerted on thepressure faces, the hooks and the undercut grooves are displacedrelative to one another, the resilient arms being deflected, so that thehooks become disengaged from the undercut grooves and the snap closurecan be released. The pressure faces advantageously lie substantiallydiametrically opposite one another, so that the snap closure can bereleased in an especially simple and practical way by simultaneouspressure on the pressure faces, for example by a user simultaneouslypressing the pressure faces together with thumb and index finger.

In an especially advantageous embodiment, the attachment is soconfigured that it has no rotational symmetry in respect of axes ofrotation in the longitudinal axis of the cartridge. For example, theattachment can in this respect have an oval or triangularcross-sectional surface. As a result, the attachment, especially when aplurality of injectate chambers is present, can be mounted on thecartridge in a specific (“correct”) way, that is to say with theinjectate chambers specifically assigned to an internal structure of theattachment. The possibility of “incorrect” mounting of attachments, asis the case with Luer lock closures in the prior art which arenecessarily rotationally symmetrical, can thus be avoided.

The attachment according to the invention can be a mixer tip whichreceives the injectate from the injectate chambers which has beenexpelled under pressure through the outlet openings by the injectionplungers and delivers it again in mixed form. Alternatively, theattachment according to the invention can be a closure cap for closingthe outlet openings of the injectate chambers. The ease of mounting andremoving the closure cap facilitated by the snap closure according tothe invention provides a practical way of storing filled cartridges (or,as the case may be, cartridges that have already been used and are stillpartly full) at a certain location, for example in a refrigerator, andthen using them again, without any risk of contamination.

The invention will now be described in greater detail with reference toan example embodiment and referring to the accompanying drawings,wherein

FIG. 1 is an exploded view of a delivery system according to theinvention,

FIG. 2 is a plan view, on an enlarged scale, of the locking clip of FIG.1, and

FIG. 3 is a perspective view of a closure cap.

Reference is made firstly to FIG. 1, which shows an exploded view of anembodiment of the delivery system according to the invention. Referencenumeral 1 indicates the cartridge of a double-barrel piston-typesyringe. The cartridge is provided with two injectate chambers each ofwhich opens into an outlet opening 2. Reference numeral 3 indicates alocking clip which is provided with resilient arms on which the undercutgrooves are arranged as part of the snap closure mechanism. The lockingclip 3 is pushed onto the cartridge, especially onto its outlet openings2. FIG. 1 also shows a mixer tip which is in turn composed of adistributor unit 4 and a mixer/delivery unit 5. The distributor unit 4is provided with inlet openings 6 which, on assembly of the arrangement,extend into the outlet openings 2 of the cartridge and receive theinjectate, which is expelled through the outlet openings 2 byintroduction of the injection plungers into the injectate chambers. Themixer/delivery unit 5 has, located inside the delivery tip 11, a spiral10 which provides for thorough mixing of the injectate. The delivery tip11 is provided with an opening 8 for delivery of the injectate. On thedistributor unit 4 there are arranged, diametrically opposite oneanother, two hooks 9 which, on assembly of the arrangement, enter intoengagement with the undercut grooves of the resilient arms of thelocking clip 3.

FIG. 2 shows a plan view, on an enlarged scale, of the locking clip 3 ofFIG. 1 in a position in which it has been pushed onto the outletopenings 2 of the cartridge 1. The locking clip 3 engages around theoutlet openings 2 of the cartridge 1 by means of incomplete rings 12,the incomplete rings 12 being joined to one another by a rib-likeconnecting element 13. The resilient arms 14 project from the incompleterings 12, each resilient arm 14 projecting in the direction towards theother incomplete ring. The resilient arms 14 can take each other'splaces by rotation of the cartridge 1 through 180° about itslongitudinal axis. The resilient arms are resiliently biased along thedirections indicated by the arrows. On the resilient arms 14 there arearranged the undercut grooves 15 in which the hooks 9 of the mixer tipengage when the arrangement is in the assembled state. In order that thehooks 9 are able to engage in the undercut grooves 15, the resilientarms must be resiliently deflected in a direction towards one another.In the engaged state, the resilient spring force of the resilient armsensures that the snap connection is secure. The resilient arms 14 arefurthermore provided with pressure faces 16 arranged diametricallyopposite one another, by means of which, with sufficient pressureperpendicular to the axial direction of the cartridge, deflection of theresilient arms is effected, so that when the pressure faces are actuatedsimultaneously the hooks 9 become disengaged from the undercut grooves15 and the snap closure can be released.

FIG. 3 finally shows a closure cap 17 for the cartridge. The closure cap17 is provided with blind sleeves 18 which, on being joined to thecartridge 1, close the outlet openings 2 of the injectate chambers. Theclosure cap 17 also has, arranged diametrically opposite, hooks 19which, on attachment of the closure cap to the cartridge, enter intoengagement with the undercut grooves 15 of the resilient arms 14 of thelocking clip 3.

1. Delivery system for fluid substances, which comprises a plunger-typesyringe in the form of a cartridge having at least one injectatechamber, which injectate chamber is provided with an injection plunger,and an attachment mounted on the cartridge at its delivery-side end anda locking clip which is arranged between a cartridge and the attachmentand, locked with the cartridge, wherein the attachment is mounted on thelocking clip by means of a releasable snap closure.
 2. Delivery systemaccording to claim 1, wherein the cartridge has at least two axiallyparallel, adjacently arranged injectate chambers having separate outletopenings.
 3. Delivery system according to claim 1 wherein there areformed on the attachment, for the purpose of its being mounted on thecartridge, two hooks which are arranged substantially diametricallyopposite; and there are formed on the delivery-side end of the cartridgetwo resilient arms which are resiliently biased on being deflected outof their rest position, each of which is provided with an undercutgroove arranged facing a hook, the hooks engaging in the undercutgrooves facing them.
 4. Delivery system account to claim 3, wherein theresilient arms are in the form of portions of an element (locking clip)mounted on the delivery-side end of the cartridge.
 5. Delivery systemaccording to claim 4, wherein the locking clip takes the form of(incomplete) rings which engage around the outlet openings of thecartridge and are joined to one another by at least one rib-likeelement, having resilient arms which project from the (incomplete)rings, which resilient arms can take each other's places by rotation ofthe cartridge through 180° about its longitudinal axis.
 6. Deliverysystem according to claim 3 wherein the resilient deflection of theresilient arms the resilient arms are provided with pressure faces inthe form of planar widened portions, the hooks becoming disengaged fromthe undercut grooves by exertion of a sufficient pressing force on thepressure faces.
 7. Delivery system according into claim 6, wherein thepressure faces lie substantially diametrically opposite one another. 8.Delivery system according to claim 1 wherein the attachment is a mixertip which receives the injectate from the injectate chambers which hasbeen expelled under pressure through the outlet openings by theinjection plungers and delivers it in mixed form.
 9. Delivery systemaccording claim 1 wherein the attachment is a closure cap for closingthe outlet openings of the injectate chambers.
 10. Delivery systemaccording to claim 1 wherein the attachment has no rotational symmetryabout axes of rotation in the longitudinal direction of the cartridge.11. Delivery system according to claim 1 wherein the snap closure locksinto place with an audible sound.